Tie-up and Wildcat strike

Tie-up noun - A crowded mass (as of cars) that impedes or blocks movement.

Wildcat strike and tie-up are semantically related. In some cases you can use "Wildcat strike" instead a noun phrase "Tie-up".

Wildcat strike noun - A strike undertaken by workers without approval from the officials of their union.

Tie-up and wildcat strike are semantically related. Sometimes you can use "Tie-up" instead a noun phrase "Wildcat strike".